Kiln



J. T. RoBsoN ET AL' May 17, 193s.

' KILN Filed Feb. 4, 1957 4 Sheets-Sheet l www ATTORNEYS May 17, 1938. J. T. RoBsoN ET AL AKILN Filed Feb.v4, 1937 4 Sheets-Shea?l 2 INVENTORS GEORGE 2P. sn vEsrE? DDD dg TAMES 7T FOESO/V BY f ATTOgNEYS May 17, 1938. J. T. RoBsON ET Al.

Filed Feb. 4, 1937 4 SheetS-Sheet 5 SYL I/E'STEP INVENTORS JAMES 77 HOPSON ATTORNEYS May 17, 1938. J. T. RoBsoN ET AL 2,117,994

KILN

Filed Feb. 4, 1937 4 Sheets-Sheet 4 INVENTORS JAMES 7.' EOBSON BY 6501265 E-SYLVESTEE ATTORNEYS Patented May 17, 1938 KILN James T. Robson, Euclid, and George lt. Sylvester, Cleveland, Ohio, assignors to Ferro Enamel Corporation, Cleveland, Ohio, a corporation of Application February 4, 1937, Serial No. 124,158

9 Claims.

This invention relates to improvements in kilns and more particularly to improvements in tunnel kilns or the like for continuously burning Vceramic ware such as china, pottery, etc.

5 However, it will be seen by those skilled in the art that a number of the features of our invention vmay be adapted to other uses such as continuous heating or annealing furnaces, etc.

In our co-pending United States patent ap- 10 plication, Serial No. 88,180, filed June 30, 1936,

we have described and claimed certain improvements in direct fired tunnel type kilns, and the apparatus described herein incorporates some of the features described and claimed in our said 15 co-pending application.

This application relates to indirectly fired or mufile type kilns and to an improved structure whereby combinations of direct and indirect heating may be obtained. It-is among the objects of our invention to provide a continuous kiln of the type described in which the temperature and atmosphere in the preheating, firing and cooling zones may be readily and accurately controlled to obtain the desired treatment of the u ware passing through the kiln. Another object of our invention is the provision of a kiln structure which may be operated as either a direct iir'ed or indirectly fired kiln in which the products of combustion may be either permitted to .o pass freely into contact with the ware or in which the ware may be maintained out of contact with the products of combustion.

Other objects of our invention will appear from the following description of one embodiment thereof, reference being had to the accompanying drawings, Iin which- Figure l is a plan section of the pre-heating and ring zones and a portion of the cooling zone of our improved kiln. This view is taken 0 substantially on line I-I of Figure 2.

Figure 1 is a view similar to Figure 1 but illustrating the remaining portion of the cooling zone of the kiln.

Figure 2 is a side elevation of that portion of s the kiln mustrated in Figure 1.

Figure 2* is a view similar to Figure 2 but' illustrating inside elevation that portion of the kiln shown in plan sectiony in Figure 18.

50 Figure 3 is an enlarged .vertical cross-section of the kiln taken substantially on line 3'3 of Figure 1.

Figure 4 is an enlarged vertical cross-section taken substantially on line l-l of Figure 1'.

Figure 5 is a horizontal cross-section taken ,on line 5 5 of Figure 6 illustrating a sliding control damper construction.

Figure 6 is an enlarged fragmentary vertical cross-section taken on line 6 6 of Figure 2 and illustrating the arrangement of the sliding ad- 5^ justable back draft control damper for the firing zone combustion chamber. l

Figure '7 is an enlarged horizontal cross-section taken on line l--l of Figure 9 and illustrating the arrangement of the adjustable plates 10 which provide means for connecting the combustion chambers with the tunnel chamber.

Figure 8 is a view of the portion of the kiln shown in Figure '1 and taken substantially on line 8-8 of `Figure 9.

Figure 9 is an enlarged vertical 'section through one of the swinging plates which provide the adjustable connection between the combustion chambers and the tunnel chamber through which the ware moves.

Figure 10 is a detached perspective view of one of the bottom refractory members which support the adjustable plates shown in Figures 7, 8 and 9.

Figure 11 is a detached perspective view oi" one of the top refractory members which support the upper ends of the closure plates shown in Figures 7, 8 and 9.

Referring' now to Figures 1, la, 2 and 2, the general arrangement-of the kiln' includes the 30 tracks i extending. into the entering chamber 2, the tracks 3 which extend throughout the length o f the kiln and on which the ware carrying cars move through the kiln, the tracks 4 which convey the. ware out of the exit chamber 5, and the .return tracks 6 which return the cars to the entering end of the kiln. Between the enter- `ing chamber 2 and the exit chamber 5 the kiln may be considered to be divided into three sections or zones, the pre-heating section being indicated at A in Figure 1, the ,firing or furnace section being indicated at B in Figure 1 and the cooling section being indicated at C in Figures 1 and 1, For convenience and toA avoid confusion these three sections or zones will be described in the order in which the warey passes through them.

The pre-heating zone The cars 1 on which the ware is loaded pass into the entering chamber 2 on the tracks l and are transferred to the tracks 3` on which they move through the tunnel chamber T. As illustrated, the cars are moved through the kiln in contact with each other and when a loaded glil in Figure 1.

flames and products of combustion into the comcar enters at the pre-heating end another car leaves the cooling end and is withdrawn to be unloaded. The ware is supported on the cars in the upper portion of the tunnel T, which upper portion may be referred to as the ware space and is sealed from the lower portion of the tunnel T by the sand seals shown at S (Figs. 3 and 4). As the cars pass into the entering chamber 2 and the end of the pre-heating zone A they are given a preliminary heating by means of circulating hot gases from the pre-heating zone. This circulation is effected by a fan or blower 8 which has an inlet pipe 9 connected to a transversely extending chamber I0 which 1n turn is connected by suitable passages to the tunnel chamber T and the side chambers I1. 'I'he outlet of the blower 8 is through the pipe II and the branch pipes I2 and I3. The pipe I2 extends into the end of the entering chamber 2 and directs a blast of hot gas at the lower portion of the ware on the cars as they enter the kiln. The pipes I3, of which there are two, one disposed on each side of the furnace, discharge hot gas into the chambers I.4 (Fig. 1) from which it is discharged against the ware through the vertical slots I5 and the openings I6. As is illustrated diagrammatically in Figure 1 the openings I5 and I6 are provided with adjustable closure members or plugs I5' and I6' whereby the circulation of gas may be controlled. These plugs are adapted to be operated from outside of the kiln to vary the size of the openings I5 and i6. Just beyond the chambers II4 in the direction of ware travel are the chambers I1. These chambers are connected at their upper ends to the transversely extending header chamber I0 and thus are adapted to withdraw gas from the tunnel chamber T under the suction o1' the blower fan 8. 'I'his is indicated by the arrows 'I'he passages which connect the chambers I1 with the tunnel chamber are also equipped with adjustable closure members I8 which are generally similar to the closure members IB'. Adjustable sliding damper plates I9 provide partial end closures for the chambers I1 whereby their connection with the combustion chambers 20 of the pre-heating zone A may be varied. 'I'he -structural arrangement of these dampers I8 is substantially the same as those which will be described later and which are i1- lustrated in detail in Figures 5 and 6:

The pre-heating zone combustion chambers 20 are equipped with angularly directed burners 2I in which oil, gas or other suitable fuel may be burned and which are adapted to direct their bustion chambers20. IIn the operation of the kiln as a completely indirect iired structure or muiile kiln the heat is transferred to the ware through the refractory walls 22 of the kiln tunnel chamber T. As is best seen in Figure 1 the burners 2I are directed so that their ames impinge against the walls 22 of the tunnel chamber at an angle thus distributing the heat more 'ectively thereovr and creatinga movement of the products of combustion in a direction opposite to the movement of ware through the tunnel. Pairs of sliding dampers 23 and 24 are disposed on either side of the burners 2 I. The dampers 23 serve to control and regulate the passage of the hot gases and products of combustion fronithe nace 'or tiring section B and the combustion chambers 20 of the pre-heating section A.

It will be understood by those skilled in the art that the sets of dampers I9, 23 and 24 awill be -regulated and controlled in such a manner that the desired distribution of heat along the tunnel chamber T will be obtained. Normally .the dampers I9 will be at'le'ast partially 'open so that the products of combustion from the ilring zone combustion chambers 25 and the pre-heating section combustion chambers 20 will be withdrawn from the kiln through the chambers I1 and the header III by the blower 8. A stack 28 extends up from the blower outlet pipe II and a The firing .zone

The zone of highest temperature in the kiln, where the actual ring of the ware takes place, is indicated .at B in Figure 1. This zone comprises chambers 25, o f somewhat greater cross section than the pre-heating zone combustion chambers 20. A plurality of burners 28, which may be supplied with oil or gas in any suitable manner (not shown), are disposed in the outer walls of each of the chambers 25. These burners are adapted to direct their ames and products of combustion against the tunnel walls 22 at an angle and in a direction opposite to that of the movement of the ware through the tunnel. Also, as shown in Figure 2, the burners 28 preferably are disposed at different heights in the kiln walls so that the heat therefrom may be evenly distributed over the inner refractory walls 22 which form the tunnel chambers. Cool air inlet or back draft ports 29 are provided at the end of the firing zone B whereby air at atmospheric temto pass the dampers 30 control of the temperature within the ring zone is facilitated. In Figures 5. and 6 the back draft control dampers 30 and their supporting arrangement are illustrated in detail. On each side of the tunnel there are two sliding damper panels 30 arranged one above the other and each extending through a slot 8| in the outer walls of the combustion chambers 25. Each damper panel 30 is provided with a handle 32 by which it may be slid toward or away from the inner refractory wall 22 of the tunnel. Packing material 33, such as asbestos or the like, is preferably disposed between the walls of the slot 3| and the dampers 30 in order to insure a close sliding iit of the dampers in the slot. As seen in Figure the damper panels are shown in their closed position and it will be understood that the operator, by pulling outwardly on the handle members 32, can adjust the positions of either one or both of the panels 30 to give the desired degree of opening. In the illustrated construction the panels 30 do not at any time completely shut off the passage in which they are disposed although they are adapted to greatly reduce the area thereof. It will be understood by -those skilled in the art that if desired these dampers may be arranged so that the passage which they control can be completely closed.

Another feature of our improved kiln construction which is common to both the pre-heating zone and the firing zone is the arrangement of adjustable plates 35 at the bottom of the side f wallsA 22 of the tunnel chamber T. 'Ihese plates are best illustrated in Figures 3, 4, '7, 8 and 9 and may be either of temperature resisting metallic alloy or of refractory material. Opposite each plate 35, in the outer walls of the kiln, is an aperture 36 which is normally closed by a removable plug 31. As seen in Figures 3 and 4 the plates 35 are in their closed position, forming a substantially gas tight wall between the inside of the tunnel T and the combustion chambers. As is seen in Figure 2 the plugged apertures 36 are regularly spaced along the entire length of the kiln and as will be seen from Figures 'I and 8 the plates 35 are preferably spaced quite close together. If it is desired to convert the kiln from muffle to direct fired, or if for any reason it is found desirable to provide a passageway between the interior of the tunnel T and any part of the side chambers of the kiln, any required number of the plates 35 may be swung back into the position illustrated in dot and dash lines-inlFig ure 9.

This swinging may conveniently be effected by removing the plugs 31 and inserting a hooked rod 36 (Fig. 9) which is adapted to engage the hole 39 in the lug 40 on the plate or door 35. As the refractory structure at the bottom portion of the inner walls 22 of the tunnel T is provided with longitudinally extending apertures 4I and 42 (see Fig. 7) it will be seen that when the plates 35 are swung back into their open position a free passage for gas is provided between the combustion chambers and the interior of the kiln around the side edges of the open plates 35. Of course, after the desired adjustment of the plates 35 has been made the plugs 36 may be reinserted.

'By suitably regulating the bottom plates 35 the operation of the kiln can be accurately controlled and any desired combination of mufiie and direct fired structure can be obtained. Figures 10 and 11 illustrate the refractory blocks which form the upper and lower supports for the bottom plates 35. 'I'he upper refractory support 43 is provided with slots 44 in which the permanent angularly disposed refractory panels 45 are held. The upper edges ofA the plates 35 rest against the surface 46 of the blocks 43 and pivot thereabout when they are swung into opened position. The bottom supporting blocks 41 are also notched or grooved at 48 for the'bottom edge of arefractory panel and are -provided with a bottom notch 49 for a closure plate l35. When it is desired tQ open one of the plates 35 it is merely necessary to insert the rod 38 through the hole 39 and lift the plate 35 until the lower edge thereof can swing over the lip 50 of the bottom plate 41,-

whereupon the plate 35 may be swung back to any desired degree of opening.

In .order to permit more accurate control of conditions within the kiln We provide tunnel relief ports 5| and combustion chamber relief ports 52 (see Figs. 2 and 3). These relief ports may,

be closed by refractory covers 53 and 54 respectively and when open provide connections between the atmosphere and the tunnel and combustion chambers. These crown relief ports are particularly effective in preventing the forcing of gas from the combustion chambers into the top of the ware chamber with resulting production of dull ware and are effective in controlling the kiln temperatures and atmosphere.

, The cooling section The cooling section C of the kiln follows the firing zone B in the direction of movement of the ware. As is seen in Figures 1, 1, 2 and 2 the cooling zone comprises anl indirect quick cooling section having refractory panel walls 55 which are cooled by air forced into the chambers 56 through the header pipes 51 and branch pipes 56. Atmospheric relief ports 59 extend through the wallsv of the kiln into the tunnel chamber T between the chambers 56 and the checker work cooling section 60. In these sections 60 of the kiln cold air is passed from the headers 51 through branch pipes 6I into a checker brick structure of any desired form. Another set of atmospheric relief ports 62 follow the checker sections 60 and are in turn followed by natural draft cooling sections 63 having refractory inner walls and sheet metal lined cooling sections 64 having metailic inner walls. The natural draft cooling sections 63 and 64 are provided with bottom openings 65 and top outlet openings 66. The natural ow of air through these cooling chambers 63 and 64 provides effective cooling at the relatively low temperatures encountered in this portion of the kiln.

A blower 61, which may be driven by a motor 61', is adapted to force air at atmospheric temperature through the pipe 68, the pipe 69, the downwardly extending pipes 10, and the headers 51 into the indirect cooling sections or chambers 56 and 60. This air passes out of chambers 56 and 60 through apertures such as 56" and 60* in the upper portions of the chambers. If desired this heated air may be conveyed by suitable pipes (not shown) and used for heating the shop or other purposes.

The blower 61 is also adapted to direct cool air through the pipes 1l and 12 to the chambers 13 (see Figs. 1a and 2a) from whence the cool air is discharged directly into the tunnel T in a direction opposite to the movement of the ware. Adjustable dampers 14 may be operated from outside the kiln by means of the operating rods 15 to control this flow of air directly into the tunnel chamber. 'I'he pipe 1i extends on beyond the branch pipes 12 and conveys air into the exit chamber 5 of the kiln.

From the above description of one embodiment of our improved kiln structure it will be ,seen that we have provided an exceedingly adaptable arrangement for ring ceramic ware or for other heating operations. With our arrangement very accurate control of both the temperature and atmosphere in all parts `of the kiln is readily obtained. The structure may be operated either as a mufiieor direct red type of heater and may be changed from one to the other form without the necessity of shutting down.

Although we have described the illustrated embodiment of our invention in considerable detail it will be understood by those skilled in the art that our structure is subject to modification and variation and we do not, therefore, wish to be limited to the specific details and forms described and illustrated herein, but claim as our invention all embodiments thereof coming within the scope bustion chamber having' a Acommon wail, said 'l5 common wall having a plurality of openings adjacent the lower portion thereof, adjustable cover panels for said openings, said panels being movable to open or close said openings, the outer walls of the combustion chamber opposite said panels having apertures through which the panels may be adjusted, and means for plugging said apertures.

2. In a kiln, walls defining a tunnel chamber ware space and a 'combustion chamber, an aperture extending through one of said walls from said combustion chamber to-said ware space, and means for closing said aperture, said closing means being operable from outside of said kiln to open said aperture.

3. A combination kiln structure having a tunnel chamber Ware space and combustion chambers disposed along each side thereof, said ware space and combustion chambers having common Walls, said walls having a plurality of openings extending therethrough, said openings having independently operable closure means.

4. A combination kiln structure having a tunnel chamber ware. space and combustion chambers disposed along each side thereof, said Ware space and combustion chambers having common walls, said walls having a plurality of openings extending therethrough, said openings having independently operable closure means, each of said closure means being adapted to be moved from outside of said kiln structure during operation of said kiln.

5. In a tunnel kiln of the indirectly red or mufile type having a tunnel chamber, said tunnel chamber including a Ware space and a combustion chamber, a relief port from saidware space to the atmosphere, a relief port from said combustion chamber to the atmosphere, independent means for closing each of said relief ports, a `port extending from said combustion chamber to said ware space and adjustable means for closing said last named port.

6. In apparatus of the type described, walls dening a tunnel chamber and a combustion chamber extending longitudinally of said tunnel chamber, and a. combustion 'chamber damper comprising a plurality of superposed plates extending t through a slot in the outer wall of said combusber extending longitudinally of said tunnel chamber, and a combustion chamber damper comprising a plurality of superposed plates extending through aslot in the outer wall of said combustion chamber, said plates having handles whereby they may be independently moved from outside said chambers to vary the eiective cross-sectional area of said combustion chamber.

9. In apparatus of the type described, walls dening a tunnel chamber and a heating chamber, and a damper comprising a plurality of superposed refractory plates extending through a slot in the outer wall of said heating chamber, said plates being adapted for sliding movement in said slot to vary the effective cross-sectional area of said heating chamber.

JAMES T. ROBSON. GEORGE R. SYLVESTER. 

